<?
function show_sections($sections){
    echo "<ul>";
    foreach($sections as $section){
        echo "<li><a href=\"{$section['href']}\">{$section['name']}</a>";
        if(isset($section['subsections'])){
            echo show_sections($section['subsections']);    
        }
        echo "</li>";
    }
    echo "</ul>";
}
?>

<? show_sections($sections); ?>